This chapter discusses cholestatic pediatric diseases. Neonatal hepatitis syndrome is an umberella terminology for conjugated bilirubinemia disorders in infants. It is also called infantile conjugated bilirubinemia disorders (ICBRD). It includes all potential causes of conjugated bilirubinemia in infants—obstructive and nonobstructive. Causes of neonatal cholestasis, neonatal hepatitis, paucity of intrahepatic bile ducts (PFIC), familial intrahepatic cholestasis, alpha 1 antitrypsin deficiency, and cystic fibrosis are covered in this chapter. Normal A1AT is a glycoprotein primarily synthesized in the liver and secreted into the serum.